Olefin polymerization using supported pentadienyl derivative-transition metal complexes

ABSTRACT

Olefin polymerization catalysts, processes for preparing the catalysts and processes for producing polyolefins utilizing the catalysts are provided. The catalysts are basically comprised of a pentadienyl derivative-transition metal complex adsorbed on an activated inorganic refractory compound.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to olefin polymerization with catalystscomprised of supported pentadienyl derivative-transition metalcomplexes, and more particularly, to supported pentadienylderivative-transitional metal catalysts, their preparation and use forpolymerizing olefins.

2. Description of the Prior Art

A great variety of olefin polymerization catalysts have been developedand used heretofore. Such catalysts can be broadly classified into threegroups: the Ziegler-Natta catalysts of the type described in BelgiumPatent 533,362 issued in 1954; the Phillips Petroleum Company silicasupported chromium catalysts of the types described in U.S. Pat. Nos.2,825,721 issued in 1958, 2,846,425 issued in 1958, 2,951,816 issued in1960, 3,887,494 issued in 1975, 4,119,569 issued in 1978 and 4,151,122issued in 1979; and the supported organo-transition metal catalysts ofthe types described in U.S. Pat. Nos. 3,709,853 issued in 1973, and3,806,500 issued in 1974, and U.S. Pat. Nos. 3,840,508 issued in 1974and 4,018,707 issued in 1977.

The supported organo-transition metal catalysts include organo chromiumcomplexes such as bis-(η-cyclopentadienyl) chromium, bis-(η⁶ -arene)chromium, tri-(η³ -allyl) chromium and tetrakis-(η³ -allyl) dichromiumsupported on inorganic oxide refractory compounds such as silica,alumina, zirconia and thoria. Another class of supported organo-metalliccatalysts is comprised of tetravalent titanium and zirconium compoundsof the formula ML_(n) X₄ --n wherein M is titanium or zirconium, L is--CH₂ C₆ H₅,--CH₂ Si(CH₃)₃ or --C₃ H₅, and X is chlorine or brominesupported on inorganic oxides. In the use of the variousorgano-transition metal catalysts, the particular transition metal, theorganic ligands and the inorganic refractory supports used all influencethe properties of the resulting polymers.

By the present invention, novel supported pentadienylderivative-transition metal olefin polymerization catalysts areprovided, the use of which results in the production of polymers havingdifferent properties from the polymers produced using prior artcatalysts.

SUMMARY OF THE INVENTION

The present invention provides novel supported pentadienylderivative-transition metal catalysts, processes for producing suchcatalysts and processes for using the catalysts for polymerizingolefins. The catalysts are comprised of transition metals of Groups IVB, V B and VI B of the Periodic Table of the Elements complexed withpentadienyl derivatives and supported on activated inorganic refractorycompounds. Preferred transition metals are titanium, vanadium,zirconium, cerium and hafnium, and a preferred pentadienyl derivative isbis-(2,4-dimethylpentadienyl). The activated inorganic refractorycompounds are preferably selected from inorganic oxides and metalphosphates. The most preferred inorganic oxides are those which arecommercially available such as silica and alumina. The most preferredmetal phosphates are the alumino-phosphates.

A supported pentadienyl derivative-transition metal catalyst of thepresent invention is prepared by activating an inorganic refractorycompound, and then contacting the activated inorganic refractorycompound with a pentadienyl derivative-transition metal complex underconditions whereby the complex is adsorbed on the refractory compound.

In preparing polyolefins using a supported pentadienylderivative-transition metal catalyst of this invention, one or moreolefins are contacted with a catalytic amount of the catalyst atpolymerization conditions. The olefins are preferably ethylene alone orethylene and a minor amount of a higher olefin, and the catalyst ispreferably a bis-(2,4-dimethylpentadienyl) titanium, vanadium, orzirconium complex supported on an inorganic oxide or metal phosphate.The polymerization process is preferably conducted under particleforming conditions at temperatures in the range of from about 60° C. toabout 110° C. and pressures in the range of from about 250 psig to about1000 psig.

It is, therefore, a general object of the present invention to providenovel supported pentadienyl derivative-transition metal catalysts,processes for preparing such catalysts and processes for polymerizingolefins using the catalysts.

Other and further objects, features and advantages of the presentinvention will be readily apparent to those skilled in the art upon areading of the description of preferred embodiments which follows.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides olefin polymerization catalysts comprisedof complexes of pentadienyl derivatives and Groups IV B, V B and VI Btransition metals supported on inorganic refractory compounds.

The pentadienyl derivative ligands useful in forming the transitionmetal complexes are comprised of pentadienyl substituted with alkylradicals having from 1 to 4 carbon atoms. Examples of such ligands are3-methylpentadienyl, 2-n-butylpentadienyl and 2,4-dimethylpentadienyl.The most preferred such ligand is 2,4-dimethylpentadienyl.

The transition metal complexes are comprised of two identicalsubstituted pentadienyl ligands with a transition metal atomtherebetween as shown by the following structural formula: ##STR1##wherein each R is hydrogen or an alkyl radical having from 1 to 4 carbonatoms or a silyl radical of the formula --SiR¹ ₃ wherein R¹ is an alkylradical having 1 to 4 carbon atoms, and M is a Group IV B, V B or VI Btransition metal. Preferably, the transition metal is selected fromtitanium, vanadium, zirconium, cerium and hafnium.

Examples of pentadienyl derivative-transition metal complexes which areparticularly suitable for use in accordance with this invention arebis-(pentadienyl) titanium, vanadium and zirconium;bis-(3-methylpentadienyl) titanium, vanadium and zirconium; andbis-(2,4-dimethylpentadienyl) titanium, vanadium and zirconium. Otherexamples are bis-(2,4-dimethylpentadienyl) cerium,bis-(2,4-dimethylpentadienyl hafnium, bis-(2,4-dimethylsilylpentadienyl)zirconium and bis-(2,4-dimethylsilylpentadienyl) vanadium. The mostpreferred pentadienyl derivative-transition metal complexes arebis-(2,4-dimethylpentadienyl) titanium, vanadium and zirconium.

The various pentadienyl-metal complexes described above can be preparedby known methods utilizing conventional techniques. For example, thepreparation of pentadienyl derivative-titanium complexes is described inthe Journal of the American Chemical Society, 1982, 104, 3737-3739, andthe preparation of pentadienyl derivative-vanadium and chromiumcomplexes is described in Journal of the American Chemical Society,1982, 104, 1120-1122.

The inorganic refractory compounds most suitable for supporting theabove described complexes are inorganic oxides and metal phosphates.Examples of preferred inorganic oxides are alumina, boria, silica,titania, zirconia and combinations thereof. Particularly preferred suchcompounds which are commercially available are alumina and silica.Suitable metal phosphates include the alumino-phosphates, e.g., aluminumorthophosphate, pyrophosphate and polyphosphates, alone or incombination with alumina. The most preferred metal phosphates are thealuminophosphates. The supports can also be modified by the addition offluorides, phosphates and phosphites as known in the art.

In preparing the supported pentadienyl derivative-transition metalcatalysts of the invention, an activated inorganic refractory compoundis contacted with a pentadienyl derivative-transition metal complexunder conditions whereby the complex is adsorbed on the refractorycompound. Generally, the activated support compound is impregnated withabout 0.1 to about 2 millimoles (mmoles) of the pentadienylderivative-metal complex dissolved in an organic solvent under dry,air-free conditions. The catalysts so prepared can be washed severaltimes with a hydrocarbon such as n-pentane and charged to a reactor inslurry form, or they can be dried and used as free flowing powders.

The inorganic refractory compounds utilized as supports for thepentadienyl derivative-metal complexes are generally activated bycalcining the compounds in air at elevated temperatures, e.g.,temperatures in the range of from about 300° C. to about 800° C., fortime periods of from about one-half hour to about twenty-four hours. Thecalcining procedure can be accomplished in a fluidized bed which, afterbeing heated at the temperature and for the time mentioned above, iscooled to a temperature in the range of from about 40° C. to about 50°C. The air is then displaced from the fluidized bed by dry argon ornitrogen followed by cooling to room temperature. The calcined supportcompounds can be stored under the inert gas in closed containers untilready for use.

Thus, the process of the present invention for preparing an olefinpolymerization catalyst of the invention, i.e., a pentadienylderivative-transition metal complex supported on an inorganic refractorycompound, is comprised of the steps of activating the inorganicrefractory compound, generally by calcining it in air, and thencontacting the activated inorganic refractory compound with thepentadienyl derivative-transition metal complex under conditions wherebythe complex is adsorbed on the refractory compound.

The supported pentadienyl derivative-transition metal catalysts of thepresent invention can be employed in various olefin polymerizationprocesses wherein one or more olefin monomers, generally having fromabout 2 to about 8 carbon atoms is contacted with a catalytic amount ofthe catalyst under polymerization conditions. Preferably, the olefinmonomers are comprised of ethylene alone or ethylene and a minor amountof a higher olefin, e.g., propylene. The polymerization reaction ispreferably carried out under slurry (particle forming) conditions. Thereaction medium can be a dry inert hydrocarbon such as isobutane,n-heptane, methylcyclohexane or benzene and the polymerization reactionis carried out at a reactor temperature within the range of from about60° C. to about 110° C. and a reactor pressure of from about 250 psig toabout 600 psig. The polyolefin produced can be recovered, treated withcarbon dioxide or water, for example, to deactivate residual catalyst,stablized with an antioxident such as butylated hydroxy toluene (BHT),and dried by conventional methods to obtain the final product. Hydrogencan be used in the reactor as known in the art to provide some controlof the molecular weight of the polymer.

The process can include the first step of contacting an activatedinorganic refractory compound with a pentadienyl derivative-transitionmetal complex under conditions whereby the complex is adsorbed on theinorganic refractory compound thereby forming a supported catalyst,followed by the step of contacting one or more olefins with a catalyticamount of the catalyst at polymerizing conditions to form thepolyolefins.

In order to further illustrate the novel organo-metal catalysts of thisinvention as well as their preparation and use, the following examplesare given. The particular components utilized in the examples are meantto be illustrative of the present invention and not limiting thereto.

EXAMPLE I

Bis-(2,4-dimethylpentadienyl) metal complexes of Ti and V weresynthesized by first converting 2,4-dimethyl-1,3-pentadienyl to thepotassium salt by reaction with well dispersed metallic potassium in atetrahydrofuran (THF) medium in the presence of triethylamine to inhibitpolymerization. The metal complex was then formed by slowly adding a THFsolution of the 2,4-dimethylpentadienyl anion to a cooled (-50° C.)suspension of the appropriate metal halide in THF. After warming to roomtemperature the THF was removed under vacuum and the product wasextracted from the residue with n-pentane. The procedures employed aredetailed below.

2,4-Dimethylpentadienylpotassiumtetrahydrofuranate, (DMPD)K.THF

3.0 g. (77 mmole) of finely divided potassium were suspended in 30 ml ofdry THF under argon. 15 ml of absolute triethylamine (dried over CaH₂)were added and the suspension was cooled to 0° C. 18 ml (139 mmole) of2,4-dimethyl-1,3-pentadiene were added dropwise over a period of atleast one hour. After warming to room temperature, the clear yellowsolution was refluxed under argon for several hours. The solution wasthen filtered, diluted with two parts pentane and stored at -30° C. toinduce crystallization. The resulting orange needles were washed withdry n-pentane and dried in vacuum for several hours at room temperature.Yield: 10 g. (49 mmol, 71%) of (DMPD)K.THF.

Bis-(2,4-dimethylpentadienyl)titanium, (DMPD)₂ Ti

3.34 g (10 mmole) of TiCl₄ (THF)₂ were suspended in 100 ml of dry THFunder argon. 0.24 g (10 mmole) of activated magnesium was then added andthe mixture was stirred for 12 hours after which time a black suspensionof TiCl₂ (THF)₂ was observed. After cooling to -78° C., a solution of4.12 g (20 mmole) of (DMPD)K.THF in 50 ml of dry THF was added dropwisethrough an addition funnel over a one hour period. After an additionalhour, the reaction mixture was allowed to warm to room temperature. Atthis point, the dark green solution was evaporated to dryness and theresidue extracted several times with 50 ml portions of dry n-pentane.The combined extracts were filtered over a small amount (2 g) of silicagel. Removal of the solvent yielded 1.6 g (6.8 mmole, 68%) of the darkgreen oil, (DMPD)₂ Ti. A 0.13 M stock solution of the product was thenprepared by adding 50 ml of dry n-pentane.

Bis-(2,4-dimethylpentadienyl)vanadium, (DMPD)₂ V

2.7 g (7.2 mmole) of VCl₃ (THF)3 were suspended in 100 ml of dry THF.0.24 g (3.6 mmole) of zinc dust were added and the mixture was refluxedfor 2 hours, until a light green suspension was obtained. After coolingto -78° C., a solution containing 3.0 g (14.4 mmole) of (DMPD)K.THF in30 ml of dry THF was added dropwise over a one hour period. Afterwarming to room temperature, the reaction mixture was worked up as inthe preceding example. Yield: 1.2 g (5 mmole, 70%) of (DMPD)₂ V.

Catalyst Preparation

With the exception of the unsupported vanadium catalyst describedhereinbelow, the catalysts were prepared by supporting the abovedescribed pentadienyl complexes on activated inorganic oxide refractorycompounds.

The inorganic oxide supports employed included Ketjen Grade B alumina, aDavison Co. alumina product, having a pore volume of about 1.7 cc/g andsurface area of about 320 m² /g; Davison Co. high pore volume aluminahaving a pore volume of about 2 cc/g and surface area of about 540 m²/g; and Davison Co. grade 952 silica having a pore volume of about 1.6cc/g and surface area of about 300 m² /g. In addition to thecommercially available oxides, several experimental supports were usedincluding aluminum orthophosphate (P/Al atom ratio of 0.9) having a porevolume of about 0.8 cc/g and surface area of about 350 m² /g and aphosphated alumina, P/Al₂ O₃, prepared by treating the high pore volumeAl₂ O₃ (previously calcined at 300° C.) with a methanol solution of H₃PO₄ at the concentration needed to provide a P/Al atom ratio of 0.1.Excess methanol was removed by suction filtration and the composite wasdried in a vacuum oven at 80° C. for 12 hours. All supports wereactivated for 3 hours at 600° C. in dry air except the silica which wasactivated for 3 hours in dry air at 700° C.

The various catalysts tested were prepared by transferring approximately1.0 g. of the activated support utilized to a Schlenk tube under argon.A total of 5 ml (0.65 mmole) of the stock solution of pentadienylderivative-metal complex used was added, and the slurry agitated untilall of the complex was absorbed as noted by the complete decolorizationof the green solution. The resulting brown catalyst was then washedseveral times with pentane and charged to the reactor either as atoluene slurry or as a free flowing powder after drying in a warmnitrogen stream.

Polymerization Conditions

All polymerization runs were carried out in a modified two liter benchreactor under slurry (particle form) conditions. The diluent wasisobutane and the reactor temperature was varied between 85° C. and 105°C. Reactor pressure was held at 550 psig during the polymerization withethylene being fed on demand.

In a series of runs, ethylene was polymerized with a known quantity ofeach catalyst, e.g., ranging from about 20 to about 150 mg, in thestirred, stainless steel reactor containing about 567 g of isobutane asdiluent and hydrogen, when used. A nominal reactor pressure of about 565psia (3.89 MPa) was employed with ethylene was supplied from apressurized reservoir as needed during each run to maintain thepressure. Generally, a run time of about 60 minutes was used at theindicated reactor temperature. A triethylaluminum cocatalyst wasrequired with the vanadium catalysts, particularly when hydrogen wasused to regulate the molecular weight of the polymer. In addition in thevanadium catalyst systems with hydrogen present, a halocarbon activator(adjuvant) was found to be needed to obtain catalytic activity.

In run 15 of Table 1B, an unsupported vanadium catalyst was used. It wasformed by treating 1 ml of a (DMPD)₂ V solution (0.1M in pentane) with 2ml of 1,2-difluorotetrachloroethane (C₂ F₂ Cl₄) under argon. The emeraldgreen color gradually faded and a fine brownish-colored precipitateformed. Ethylene was bubbled through the suspension for about 5 minutesat atmospheric pressure resulting in polymer coated catalyst particles.The particles were separated by filtration, washed several times withn-pentane and dried at room temperature under vacuum, yielding 1.3 g ofpolymer coated catalyst particles. In run 15 of Table 1B 0.12 g of the"prepolymer catalyst" was charged to the reactor and used in combinationwith 0.75 mmole of triethylaluminum (TEA) to polymerize ethylene.

The results obtained are presented in Tables 1A and 1B below. In theTables, the significance of the abbreviations and the test methodsemployed in determining the physical properties of the polymers are asfollows:

Calculated productivity (g/g/hr) is based on grams polymer per gramsolid catalyst per hour.

Melt index (MI), g/10 minutes - ASTM D 1238, condition E.

High load melt index (HLMI), g/10 minutes - ASTM D, condition F.

Density, g/cc - ASTM D 1505.

Flexural modulus (Flex Mod), MPa - ASTM D 790.

Melt viscosity (MV) M poise - Melt viscosity data are obtained by meansof a Rheometrics Dynamic Spectrometer (RDS) at 230° C. using parallelplate geometry. Strain amplitude is 1% (or 5%), nitrogen gas is used inthe sample chamber and the oscillatory frequency can be varied from 0.1to 500 radians/second. From these data in turn can be calculated dynamiccomplex viscosity/η*/ as described in Chapter 1 of the "ViscoelasticProperties of Polymers", by Terry, published in 1961 by Wiley. Thevalues obtained are directly related to molecular weight, with thehigher the value the higher the molecular weight. It has been shown fora commercially available ultra high molecular weight polyethylene(UHMWPE) (Hostalen GUR, American Hoechst) that /η*/, when determined at1% strain and 0.1 radian/second at 230° C. has a value of about 39.Higher values then indicate even higher molecular weight polymers havebeen made.

                                      TABLE 1A                                    __________________________________________________________________________    Ethylene Polymerization with (DMPD).sub.2 Ti Catalysts                                       Reactor                                                                             Calculated        Flex                                   Run      Run Temp                                                                            Hydrogen                                                                            Productivity                                                                         MI/HLMI                                                                             Density                                                                            Mod.                                                                             MV                                  No.                                                                              Support                                                                             °C.                                                                          psi   g/g/hr g/10 min                                                                            g/cc MPa                                                                              MPoise                              __________________________________________________________________________    1  Al.sub.2 O.sub.3 .sup.(a)                                                           96    0     5700   0/0   0.932                                                                               806                                                                             65                                  2  Al.sub.2 O.sub.3 .sup.(a)                                                           96    50    6000   0/0   0.946                                                                              1114                                                                             20                                  3  Al.sub.2 O.sub.3 .sup.(a)                                                           96    100   4000   0/0.01                                                                              0.946                                                                              1145                                                                             --.sup.(d)                          4  Al.sub.2 O.sub.3 .sup.(a)                                                           85    0     1600   0/0   0.932                                                                               769                                                                             72                                  5  Al.sub.2 O.sub.3 .sup.(a)                                                           105   0     2300   0/0   0.931                                                                               785                                                                             37                                  6  Al.sub.2 O.sub.3 .sup.(b)                                                           96    50    3100   0/0.02                                                                              0.944                                                                              1038                                                                             --                                  7  Al.sub.2 O.sub.3 .sup.(b)                                                           96    100    900   0/0.06                                                                              0.954                                                                              1279                                                                               4.4                               8  P/Al.sub.2 O.sub.3 .sup.(c)                                                         96    0     4000   0/0   0.934                                                                               872                                                                             54                                  9  AlPO.sub.4                                                                          96    0      200   0/0   --   -- --                                  10 SiO.sub.2                                                                           96    0      100   0/0   --   -- --                                  __________________________________________________________________________     .sup.(a) Ketjen Grade B alumina.                                              .sup.(b) Davison high pore volume alumina.                                    .sup.(c) Phosphated high pore volume alumina.                                 .sup.(d) A dash signifies not determined.                                

                                      TABLE 1B                                    __________________________________________________________________________    Ethylene Polymerization with (DMPD).sub.2 V Catalysts, 96° C.                  Reactor                                                                             Calculated        Flex                                          Run     Hydrogen                                                                            Productivity                                                                         MI/HLMI                                                                             Density                                                                            Mod.                                                                              MV                                        No.                                                                              Support                                                                            psi   g/g/hr g/10 min                                                                            g/cc MPa MPoise                                    __________________________________________________________________________    11 Al.sub.2 O.sub.3 .sup.(a)                                                          0      1000  0/0   0.933                                                                              924 --.sup.(d)                                12.sup.(b)                                                                       Al.sub.2 O.sub.3                                                                   0      1400  0/0   0.932                                                                              845 89                                        13.sup.(b)                                                                       AlPO.sub.4                                                                         0      2600  0/0   0.933                                                                              873 63                                        14.sup.(b)                                                                       AlPO.sub.4                                                                         50      700   11/770                                                                             0.971                                                                              1769                                                                              --                                        15 None 0     144000.sup.(c)                                                                       0/0   0.926                                                                              602 124                                                      2720.sup.(e)                                                   __________________________________________________________________________     .sup.(a) Ketjen Grade B alumina.                                              .sup.(b) Run with 0.03 mmole TEA and 2 mmoles C.sub.2 F.sub.2 Cl.sub.4 as     reactor adjuvants.                                                            .sup.(c) Calculated productivity based on grams polymer/gram vanadium.        .sup.(d) A dash signifies not determined.                                     .sup.(e) Based on the polymer coated catalyst, calculated productivity is     2720 g/g/hr.                                                             

The productivity results given in Tables 1A and 1B show that thebis-(2,4-dimethylpentadienyl) metal complexes of Ti and V, whensupported on inorganic oxides, particularly alumina, phosphated aluminaand aluminum phosphate, are active ethylene polymerization catalysts.Silica and aluminum phosphate are not as effective as alumina forsupporting the complexes of Ti and are not usually employed when suchcomplexes are used. In general, the supported Ti complexes exhibithigher activities than the corresponding V complexes.

In the absence of reactor hydrogen all of the polymers produced with thesupported catalysts had zero regular melt indicies and high load meltindicies ranging from zero to 0.06. Such values are indicative of veryhigh molecular weight polymers. Based on melt viscosity values of 37-89Mpoise, for polymers made with the Ti and V complexes, the polymers infact are in the ultrahigh molecular weight range. The commerciallyavailable UHMWPE (Hostalen GUR) mentioned above has a value of 39M poiseunder the same test conditions.

In the presence of reactor hydrogen, the activity of the Ti catalystsdeclines and the V catalysts are deactivated altogether. However, someactivity of the V catalysts can be restored by the addition of ahalocarbon activator to the reactor as shown in run 14 of Table 1B.

The melt index response to hydrogen with the catalysts is dependent uponthe metal of the complex, the support, and the activation temperature ofthe support. The Ti catalysts have very low hydrogen response since onlyfractional HLMI polymers were made. The V catalysts, in contrast, have agood hydrogen response, and consequently, a range of melt indicies canbe obtained by adjusting the hydrogen concentration in the reactor.

EXAMPLE II

The catalysts of the present invention were compared with catalystscomprised of supported organo-chromium compounds selected from bis(η⁵-cyclopentadienyl)chromium and the zerovalent complexes bis(η⁶-cumene)chromium and bis(η⁶ -mesitylene)chromium. The comparisoncatalysts were prepared in the same manner as described above. That is,a hydrocarbon solution of the organo-chromium compound was impregnatedon the activated support in a dry, oxygen-free atmosphere. The resultingcomplex, after washing, was employed in slurry form or as a dry, freeflowing powder in ethylene polymerizations as described above.

The ethylene polymers produced with the supported catalysts wererecovered and stabilized as above. Their structural properties weredetermined by means of infrared spectroscopy, ¹³ C-NMR spectroscopy andsize exclusion chromatography (SEC). The ¹³ C-NMR spectra were obtainedat 125° C. with a Varian XL-200 NMR spectrometer. The molecular weightdata were obtained with a SEC unit (Du Pont 830 instrument).

The results are set forth in Tables 2A, 2B and 2C below.

                  TABLE 2A                                                        ______________________________________                                        End Group Characterization by Infrared Spectroscopy                                                    Terminal                                                                      Vinyl  Methyl                                                                 Groups Groups                                        Run  Metal               Per    Per   vinyl/methyl                            No.  Complex    Support  1000 C 1000 C                                                                              Ratio                                   ______________________________________                                        1    (DMPD).sub.2 V                                                                           AlPO.sub.4                                                                             0.3    0.7   0.43                                    2.sup.(b)                                                                          (DMPD).sub.2 V                                                                           AlPO.sub.4                                                                             0.5    3.8   0.13                                    3.sup.(a)                                                                          (CP).sub.2 Cr                                                                            AlPO.sub.4                                                                             0.05   3.8   0.01                                    4    (CUM).sub.2 Cr                                                                           AlPO.sub.4                                                                             4.2    5.7   0.74                                    5.sup.(a)                                                                          (CUM).sub.2 Cr                                                                           AlPO.sub.4                                                                             4.3    6.4   0.67                                    6    (DMPD).sub.2 Ti                                                                          Al.sub.2 O.sub.3                                                                       0.2    0.6   0.33                                    7.sup.(b)                                                                          (DMPD).sub.2 Ti                                                                          Al.sub.2 O.sub.3                                                                       0.4    0.9   0.44                                    8.sup.(c)                                                                          (DMPD).sub.2 Ti                                                                          Al.sub.2 O.sub.3                                                                       0.3    0.9   0.33                                    ______________________________________                                         .sup.(a) 10 psi H.sub.2 in reactor.                                           .sup.(b) 50 psi H.sub.2 in reactor.                                           .sup.(c) 100 psi H.sub.2 in reactor.                                     

                                      TABLE 2B                                    __________________________________________________________________________    Branching Configuration By .sup.13 C-NMR Spectroscopy                                        Reactor                                                                             Mole Percent                                             Run                                                                              Metal       Hydrogen                                                                            Unsat./.sup.(a)                                                                    Methyl                                                                             Longer.sup.(b)                                                                     Total                                     No.                                                                              Complex                                                                              Support                                                                            psi   sat. Branches                                                                           Branches                                                                           Branches                                  __________________________________________________________________________    10 (DMPD).sub.2 V                                                                       AlPO.sub.4                                                                         50    0    .06  .04  .10                                       11 (CUM).sub.2 Cr                                                                       P/Al.sub.2 O.sub.3                                                                  0    .50  .10  .24  .34                                       12 (CP).sub.2 Cr                                                                        P/Al.sub.2 O.sub.3                                                                 10    0    .32  none .32                                       13 (CP).sub.2 Cr                                                                        P/Al.sub.2 O.sub.3                                                                 50    0    .51  none .51                                       __________________________________________________________________________     .sup.(a) Ratio of terminal vinyl to methyl end groups.                        .sup.(b) Ethyl and butyl.                                                

                                      TABLE 2C                                    __________________________________________________________________________    Molecular Weight By SEC                                                       Run                                                                              Metal       Low MW Component                                                                         High MW Component                                                                        Total Polymer.sup.(b)                    No.                                                                              Complex                                                                              Support                                                                            Wt. %.sup.(a)                                                                       MW.sub.max                                                                         Wt. %.sup.(a)                                                                       MW.sub.max                                                                         M.sub.n                                                                           M.sub.w                                                                            HI                              __________________________________________________________________________    14 (DMPD).sub.2 V                                                                       AlPO.sub.4                                                                         0     --   100   18700                                                                              6900                                                                              73,800                                                                             10.7                            15 (CP).sub.2 Cr                                                                        AlPO.sub.4                                                                         0     --   100   65800                                                                              26800                                                                             131,000                                                                            4.9                             16 (MES).sub.2 Cr                                                                       AlPO.sub.4                                                                         50    1400  50   23100                                                                              2560                                                                              77,600                                                                             30.3                            __________________________________________________________________________     .sup.(a) The relative weight percent and MW.sub.max values of the low and     high molecular weight components were calculated from the integrated peak     intensity (accum. wt. %) and the peak maxima respectively.                    .sup.(b) M.sub.n is number average molecular weight. M.sub.w is weight        average molecular weight. HI is heterogeneity index which is the value        obtained by dividing M.sub.w by M.sub.n. The larger the HI value, the         broader the molecular weight distribution of the polymer.                

The results set forth in Tables 2A, 2B and 2C show that polymers withsignificant differences in short chain branching, end group unsaturationand molecular weight distribution are obtained using the supportedpentadienyl derivative-metal catalysts of this invention as compared tothose obtained using supported prior art catalysts.

EXAMPLE III

Other catalysts of the present invention were prepared using proceduressimilar to the procedures of Example 1 and using other metal chlorides(M=Zr, V, Ce) and another pentadienyl ligand 1,5-trimethylsilylpentadienyl, according to the following equations:

    ZrCl.sub.4 +4[1,5-(SiMe.sub.3).sub.2 C.sub.5 H.sub.5 ]K →Zr[1,5-(SiMe.sub.3).sub.2 C.sub.5 H.sub.5 ].sub.2

    VCl.sub.2 +2[1,5-(SiMe.sub.3).sub.2 C.sub.5 H.sub.5 ]K→V[1,5-(SiMe.sub.3).sub.2 C.sub.5 H.sub.5 ].sub.2

    CeCl.sub.13 +3[2,4-Me.sub.2 C.sub.5 H.sub.5 ]K→Ce[2,4-Me.sub.2 C.sub.5 H.sub.5 ].sub.2

Catalysts were then made by depositing these compounds from a toluenesolution onto Ketjen Grade B alumina which had been calcined previouslyin nitrogen at 600° C.

Polymerization runs utilizing the above described catalysts were carriedout and the properties of the polymers formed were determined asdescribed in Example I above. The results are given in Table 3 below.

                                      TABLE 3                                     __________________________________________________________________________    Ethylene Polymerization With Various Supported Pentadienyl-Transition         Metal Complexes                                                                                               Calculated                                                                           Wt. %                                  Pentadienyl-                                                                          Structural                                                                              Support                                                                             Reactor Productivity                                                                         Metal on                               Metal Complex                                                                         Formula   Compound                                                                            Hydrogen (psi)                                                                        g/g metal/hr                                                                         Support                                                                            MI HLMI                           __________________________________________________________________________    Bis-(2,4-di- methylsilyl- pentadienyl) zirconium                                       ##STR2## Al.sub.2 O.sub.3                                                                    0       3590   1.4  0  0                              Bis-(2,4-di- methylsilyl- pentadienyl) vanadium                                        ##STR3## Al.sub.2 O.sub.3                                                                    0       645,000                                                                              0.077                                                                              0  0                              Bis-(2,4-di- methylsilyl- pentadienyl) vanadium                                        ##STR4## Al.sub.2 O.sub. 3                                                                   10      368,000                                                                              0.077                                                                              0  0                              Bis-(2,4-di-                                                                          Ce(DMPD).sub.2                                                                          Al.sub.2 O.sub.3                                                                    0       1051   2.75 0  0                              methylpenta-                                                                  dienyl)                                                                       cerium                                                                        __________________________________________________________________________     .sup.1 Ketjen Grade B alumina                                            

The productivity results given in Table 3 show that the variouscatalysts tested, and particularly Bis-(2,4-dimethylsilyl-pentadienyl)vanadium, are active ethylene polymerization catalysts.

Thus, the present invention is well adapted to carry out the objects andattain the ends and advantages mentioned as well as those inherenttherein. While numerous changes in components, procedures and processsteps may be made by those skilled in the art, such changes areencompassed within the spirit of this invention as defined by theappended claims.

We claim:
 1. A process for preparing polyoflefins comprising contactingone or more olefins with a catalystic amount of a pentadienylderivative-transition metal complex supported on an inorganic refractorycompound at polymerization conditions, said pentadienylderivative-transition metal complex being selected from the grouprepresented by the structural formula: ##STR5## wherein each R ishydrogen, a methyl radical or a silyl radical of the formula --SiR¹ ₃wherein R¹ is a methyl radical, and M is a transition metal selectedfrom titanium, vanadium, zirconium, cerium and hafnium.
 2. The processof claim 1 wherein said olefins are comprised of ethylene alone orethylene and a minor amount of a higher olefin.
 3. The process of claim2 wherein said higher olefin is 1-hexene.
 4. The process of claim 1wherein said pentadienyl derivative-transition metal complex is selectedfrom the group consisting of bis-(2,4-dimethylpentadienyl) titanium,vanadium and zirconium and bis-(2,4-dimethylsilylpentadienyl) zirconiumand vanadium.
 5. The process of claim 1 wherein said inorganicrefractory compound is selected from the group consisting of inorganicoxides and metal phosphates.
 6. The process of claim 4 wherein saidinorganic refractory compound is an inorganic oxide selected from thegroup consisting of alumina, boria, silica, titania, zirconia andcombinations thereof.
 7. The process of claim 4 wherein said inorganicrefractory compound is an alumino-phosphate.
 8. The process of claim 1which is conducted under particle forming condition at a temperature inthe range of from about 60° C. to about 110° C. and a pressure in therange of from about 250 psig to about 1000 psig.
 9. A process forpreparing polyolefins comprising the steps of:(a) contacting anactivated inorganic refractory compound with a pentadienylderivative-transition metal complex selected from the group consistingof bis-(2,4-dimethylpentadienyl) titanium, vanadium, and zirconium andbis-(2,4-dimethylsilylpentadienyl) zirconium and vanadium underconditions whereby said complex is adsorbed on said inorganic refractorycompound thereby forming a supported organo-metal catalyst; and (b)contacting one or more olefins with a catalytic amount of said supportedorgano-metal catalyst at polymerizing conditions thereby forming saidpolyolefins.
 10. The process of claim 9 wherein olefins are comprised ofethylene alone or ethylene and a minor amount of 1-hexene.
 11. Theprocess of claim 9 wherein said inorganic refractory compound isselected from the group consisting of inorganic oxides and metalphosphates.
 12. The process of claim 9 wherein said inorganic refractorycompound is an inorganic oxide selected from the group consisting ofalumina, boria, silica, titania, zirconia and combinations thereof. 13.The process of claim 9 wherein said inorganic refractory compound is analumino-phosphate.
 14. The process of claim 9 which is conducted underparticle forming conditions at a temperature in the range of from about60° C. to about 110° C. at a pressure in the range of from about 250psig to about 600 psig.